Here's a place where I can post my thoughts on new papers, provide updates on my projects, and post info that will eventually be on my website The Theropod Database - http://theropoddatabase.com/ . It will center on theropods, but may delve into other topics as well such as phylogenetics.

Friday, January 28, 2011

You may remember my prior criticism of Hone and Benton (2008), who merged matrices when examining pterosaur relationships, but didn't combine equivalent OTUs. They had both Lepidosauromorpha AND the lepidosauromorphs Gephyrosaurus, Sphenodontia and Squamata. And they had both Choristodera AND the choristoderes Lazarussuchus, Cteniogenys and Champsosaurus. Disturbingly, each more inclusive OTU did not clade with its exemplars in their trees.

Well now we have another example of using matrices without taking equivalent OTUs into account. Yates (2004) had a sauropodomorph matrix where he tried two sets of outgroups. One was Herrerasaurus and (Neo)Theropoda, another was Ornithischia and an expanded Theropoda including Herrerasaurus. In the recent description of Chuxiongosaurus, Lu et al. (2010) used Yates' matrix but just ran the whole thing without noticing this. Thus we have a cladogram with "Neotheropoda" sister to "Theropods"... :| Herrerasaurus is the outgroup, probably because it is listed first in Yates' matrix, and Lu et al. didn't realize PAUP makes the first listed OTU the outgroup automatically. Thus Ornithischia (which really should be the outgroup) is sister to the double-theropod clade. What makes it especially sad is even if Lu et al. didn't read Yates' text, Yates labels the OTUs "Herrerasaurus ischigualastensis", "Theropoda (excluding Herrerasaurus)" and "Theropoda (including Herrerasaurus)" in his matrix. How can you copy codings from that and not realize those aren't all independant taxa?!

As an aside, I'd like to see Chuxiongosaurus compared to Yunnanosaurus and Jingshanosaurus. Thanks to Brad McFeeters for alerting me to this mess.

Thursday, January 20, 2011

Following along our survey of Zhao's sauropods, note he originally spelled this one with an 'o', unlike most subsequent authors.

"Damalosaurus" Zhao, 1983
"Damalasaurus laticostalis" Zhao, 1985
"Damalasaurus magnus" Zhao, 1985
= "Damalosaurus laticostalis" [sic] Chure and McIntosh, 1989
= "Damalosaurus magnus" [sic] Chure and McIntosh, 1989
= "Damalasaurus magnas" [sic] Zhang and Li, 1997Etymology- Named for Damala Mountain in Qamdo, with the species referring to wide ribs (laticostalis) or large size (magnus).Early JurassicMiddle Daye Group, Daye, Qamdo County, Tibet, ChinaMaterial- (~15 m) specimen including dorsal ribComments- The species is listed as "magnus" in the text, but "laticostalis" in the plate caption. Olshevsky (1991) listed "laticostalis as the type, though I consider it probable only one species is intended by Zhao since two are never present in faunal lists together (Zhao and Cheng, 1985; Zhang and Li, 1997; Fang et al., 2006). Fang et al. use "laticostalis" for the species, suggesting it is the intended one since Zhao is a coauthor. Zhao (1985) includes a photograph of a dorsal rib in situ, which the length estimate above is taken from assuming proportions like Barapasaurus. Glut (1997) incorrectly stated it is Middle Jurassic in age. Weishampel et al. (2004) list this as an undescribed sauropod in their faunal list.

Dorsal rib of "Damalosaurus laticostalis/magnus" in matrix, from Zhao (1985).

Relationships- Stated by Zhao (1983, 1985) to be a primitive sauropod. Chure and McIntosh (1989) listed it as a cetiosaurid, while Lambert (1990) and Olshevsky (1991) listed it as a brachiosaurid. Glut (1997) only listed it as Sauropoda incertae sedis. Fang et al. (2006) place it in Cetiosauridae, noting again it's a primitive sauropod. As those authors placing it in Brachiosauridae have never seen the specimen, and brachiosaurids are currently unknown from Asia or the Early Jurassic, that assignment seems less likely. Since Cetiosauridae is currently viewed as a grade of basal eusauropods, "Damalosaurus" is here placed as Sauropoda incertae sedis.

Tuesday, January 18, 2011

"Oshanosaurus youngi" Zhao, 1985Etymology- Oshan is a variant of Eshan, a county in Yunnan it was found in. The species name probably references famed Chinese paleontologist Young Zhongjian.Hettangian, Early Jurassic
Zhangjiawa Member of the Lufeng Formation, Dianchung, Eshan County, Yunnan, China

Comments- Glut (1997) incorrectly stated it was found in Mongolia. I suspect this is an old name for Eshanosaurus, which has the same etymology, is also from the Dianzhong Basin of Eshan County, was discovered by Zhao in 1971 and was later described in part by him (Zhao and Xu, 1998; Xu et al., 2001). Relationships- Stated by Zhao (1985) to be a primitive sauropod. Chure and McIntosh (1989), Lambert (1990) and provisionally Olshevsky (1991) listed it as a cetiosaurid. Glut (1997) listed it as a possible heterodontosaurid or "geranosaur", possibly because Zhao mentions it in the same sentence as Dianchungosaurus. As traditional Cetiosauridae now refers to a grade of basal eusauropods, ignoring the Eshanosaurus connection I would retain "Oshanosaurus" as Sauropoda incertae sedis.
While Eshanosaurus is corrently believed to be a therizinosaur, therizinosaur mandibles are quite similar to those of sauropodomorphs and were poorly known in the 1980s. Indeed, Eshanosaurus' mandible resembles those of basal eusauropods (e.g. Shunosaurus) more than basal sauropodomorphs in having a dorsoventrally expanded symphysis, anterior teeth the largest, a basolingual swelling on its teeth, a lingual median ridge on its teeth, and tooth roots expanded to be broader than their crowns. However, it is unlike eusauropods in having a narrow symphysis, smooth enamel, a lateral dentary ridge and perpendicular serrations on its teeth. Given Eshanosaurus' similar incongruity when considered as a therizinosaur (more derived than the much later Falcarius in having a decurved symphysis, lateral ridge and enlarged serrations; not to mention early appearence compared to other coelurosaurs), it may be convergent with both eusauropods and therizinosaurs.

Comments- Though usually believed to be a preliminary name for Datousaurus (e.g. Olshevsky, 1991), "Lancangosaurus" was first reported by Zhao (1980) in relation to a Dapuka specimen, not the Xiashaximiao Datousaurus. Listed characters are large skull, large spatulate teeth which decrease gradually in size posteriorly, a thick mandible and robust limbs. Dong et al. (1983) believed the teeth were congeneric with those from the Wujiaba Quarry of the Shangshaximiao Formation, which they described as belonging to Omeisaurus junghsiensis and O. fuxiensis. Zhao (1985) figures teeth in situ, though the photograph is unclear. Note Olshevsky (1991) switched the authorship for the variants "Lancanjiangosaurus" and "Lancangjiangosaurus". Glut (1997) incorrectly listed it as being Late Jurassic in age. Fang et al. (2006) note additional material from lower in the same formation. Given the etymology, either "Lancangosaurus" or "Lancangjiangosaurus" would be the most accurate names.Relationships- "Lancanjiangosaurus" was stated by Zhao (1983) to be a bothrosauropodoid, in which he includes spatulate-toothed taxa like camarasaurids and brachiosaurids. Zhao (1985) notes it is a sauropod similar to Cetiosaurus. Chure and McIntosh (1989) listed it as a cetiosaurid, as does Olshevsky (1991) provisionally, while Lambert (1990) listed it as a brachiosaurid. Glut (1997) merely referred it to Sauropoda incertae sedis. Most recently, Fang et al. (2006) place it in Cetiosauridae. The known characters are found in both basal eusauropods like Omeisaurus and camarasaurids, though the age, locality and Zhao's opinion all favor the former identification. Whether Dong et al. are correct in placing it close to Omeisaurus is unknown, and for now I recommend keeping it as Eusauropoda incertae sedis.References- Zhao, 1980. [Mesozoic vertebrate-bearing beds and stratigraphy of northern Xinjinag: Report of Paleontological Expedition to Xinjiang IV.] Memoirs of the Institute of Vertebrate Palaeontology and Palaeoanthropology, Academia Sinica A. 15, 1-119.
Dong, Zhou and Zhang, 1983. [Dinosaurs from the Jurassic of Sichuan]. Palaeontologica Sinica, New Series C. 162(23), 1-136 .
Martin-Rolland, 1999. Les sauropodes chinois [The Chinese sauropods]. Revue Paléobiologie, Genève. 18(1), 287-315.

"Microdontosaurus" Zhao, 1983
"Microdontosaurus dayensis" Zhao, 1985Etymology- The genus name refers to small teeth, while the species name references the Daye township in Qamdo.Middle Jurassic
Middle Dapuka Group, Dabuka, Qamdo County, Tibet, China
Material- specimen seemingly including teethComments- As Gilmore (1902) already named an ichthyosaur Microdontosaurus petersonii (currently a junior synonym of Baptanodon discus), Zhao's sauropod will need a new name if it is officially described in the future. Glut (1997) incorrectly dates the species to 1983 and places it in the Late Cretaceous. Relationships- Stated by Zhao (1983) to be a homalosauropodoid, in which he includes peg-toothed taxa like diplodocoids (including mamenchisaurids in his view) and titanosaurs. Similarly, Zhao (1985) states it is a primitive peg-toothed sauropod. Chure and McIntosh (1989) listed it as a cetiosaurid, Lambert (1990) listed it as a diplodocid, and Olshevsky (1991) as a melanorosaurid. Glut (1997) merely refers it to Sauropoda incertae sedis. Most recently, Fang et al. (2006) place it in Brachiosauridae.
A placement outside of Sauropoda is unlikely for a Middle Jurassic taxon (though not unheard of- see Yunnanosaurus? youngi), suggesting Olshevsky's assignment is incorrect. While traditionally only diplodocoids and titanosaurids were seen as having nonspatulate teeth, they are also found in more basal brachiosaur-grade titanosauriforms and even some basal eusauropods like Shunosaurus. This suggests Fang et al.'s assignment to Brachiosauridae may be most accurate, especially as Zhao is a coauthor while Chure, McIntosh and Lambert have not seen the specimen. Since Brachiosauridae as traditionally conceived is paraphyletic, "Microdontosaurus" is here tentatively assigned to Titanosauriformes incertae sedis.References- Gilmore, 1902. Discovery of teeth in Baptanodon, an ichthyosaurian from the Jurassic of Wyoming. Science. 16(414), 913-914.

Saturday, January 8, 2011

This will be a crazy month for the Theropod Database Blog, with a comparative lack of theropods. As part of my study of "Dachongosaurus", I examined Yates' (2007) matrix to see which characters it had. That analysis has been modified and added to by several authors, so I combined all of these changes to make the new version as most recently published. This involved-

Unlike Ezcurra's matrix, guaibasaurids aren't necessarily monophyletic (and note pruning Agnosphitys or Panphagia does not make them monophyletic), but are all sauropodomorphs unlike Yates' original. Also like Ezcurra but unlike Yates, Eoraptor is sister to Avepoda.

In Ignavusaurus' description, it was basal to Efraasia, but here it's more derived. Unlike Yates et al. (2010) but like Yates (2004), Gryponyx is a massospondylid, and unlike Sertich and Loewen (2010) the Lufengosaurus clade are also massospondylids. Yunnanosaurus is now basal to Jingshanosaurus.

Thursday, January 6, 2011

The first entries in this series are sauropodomorphs, so repeat some information from the first post of the year (including photos for completeness sake). Remember general references are given in part 1.

Specimen of "Dachongosaurus yunnanensis" (after Zhao, 1985).

"Dachongosaurus yunnanensis" Zhao, 1985
"Dachungosaurus yunnanensis" Zhao, 1985Etymology- Dachong refers to the red color of the beds it was found in, while the species name refers to the province it was discovered in.Sinemurian, Early Jurassic
Shawan Member of the Lufeng Formation, Dafongtian, Yunnan, China
Material- (~9.7 m) partial skeleton including at least nine dorsal vertebrae (~118 mm), seventeen dorsal ribs, femur (~955 mm)Comments- "Dachongosaurus" is used in the text, while "Dachungosaurus" is used in the plate caption. Which will be used (if either) if it is eventually officially named is unknown.
A photo of the skeleton in situ is in Zhao (1985). Li et al. (1998) include Dachongosaurus yunnanensis in a faunal list. The length is estimated based on comparison with Jingshanosaurus, using the femoral length estimated from the photo.Relationships- Stated by Zhao (1985) to be a basal sauropod with some derived features. Lambert (1990) listed it as a cetiosaurid, which Olshevsky (1991) also referred it to provisionally. Glut (1997) merely listed it as Sauropodomorpha incertae sedis. While few details are available from the photo, the femur appears to be strongly sigmoidal unlike the condition in sauropods. While the size is large for a non-sauropod, it is approached by some taxa such as Jingshanosaurus (femur 880 mm). It may in fact be a Jingshanosaurus specimen, though the material itself has not yet been described (contra the possibility alluded to on Wikipedia), as the Jingshanosaurus holotype is positioned differently and Xixiposaurus is much smaller. For now I recommend placing it as Plateosauria incertae sedis, as the large size is at least unknown in more basal sauropodomorphs. Reference- Li, Zhang and Cai, 1998. The Characteristics of the Composition of the Trace Elements in Jurassic Dinosaur Bones and Red Beds in Sichuan Basin. Geological Publishing House, Beijing. 155 pp.

Wednesday, January 5, 2011

Since I've now acquired Zhao's 1985 paper (graciously translated by Leo Sham), the next several posts will be different than usual in that they won't involve theropods. Ever since I read Lambert's (1990) Dinosaur Data Book (the inspiration for my website's title, btw), I've been intrigued by the obscure dinosaurs named by Zhao- "Damalasaurus", "Tianchungosaurus", "Ngexisaurus", etc.. What were these? As I learned more about dinosaurs, I found out even most professionals didn't know. Over the past week I've poured over all of the available information on these taxa to present the most detailed treatment they've ever received. Some material from my last post will be repeated, but I've also uncovered earlier uses for some genera than even Olshevsky's lists show, and have a few new ideas of my own. The theropods are on my website already (with some minor updates forthcoming), but since it doesn't include sauropodomorphs or ornithischians, I've decided to place the non-theropod summaries on this blog. There are several references relevant to most taxa, and these are given below and not repeated in every entry. The first taxon is one of the most obscure, largely because Zhao didn't create a new genus for it...

Lufengosaurus "changduensis" Zhao, 1985Etymology- Changdu is an alternative spelling of Qamdo, the county it was discovered in.Early Jurassic
Middle Daye Group, Qamdo County, Daye, Tibet, China
Comments- This species is apparently illustrated by Yang (1986). Weishampel et al. (2004) include it in their faunal list along with an undescribed prosauropod which may be the same thing.Relationships- Listed as a plateosaurid by Chure and McIntosh (1989) and Fang et al. (2006), and as an undescribed anchisaurid by Weishampel (1990). Lufengosaurus has more recently been placed as a basal massopod, but being undescribed, there is no published evidence "changduensis" belongs in Lufengosaurus or is distinct from L. huenei. Reference- Yang, 1986. The Jurassic System. in Yang, Cheng and Wang (eds.). The Geology of China. Clarendon Press. 140-152.

General References- Zhao, "1983" [unpublished]. The Mesozoic vertebrate remains of Xizang (Tibet), China. The Series of the Scientific Expeditions to the Qinghai-Xizang Plateau. Palaeontology of Xizang. 2, 1-200.

Zhang and Li, 1997. Mesozoic Dinosaur Localities in China and Their Stratigraphy. In Wolberg, Sump and Rosenberg (eds.). Dinofest International, Proceedings of a Symposium sponsered by Arizona State University. A Publication of The Academy of Natural Sciences. 265-273.

Sunday, January 2, 2011

Happy New Year! In celebration, here's a rare sauropod post. Tired of other sauropod picture blogs that show you common taxa like Giraffatitan or the tons of Morrison genera? Well here are three of the most poorly known sauropods that have ever been pictured, thanks to the copy of The Jurassic System of China I got for Christmas. I can stumble through with OCR and Babelfish, but if anyone reading can read Chinese, I'd be grateful if you'd translate the 3.5 pages of text for me. These are the only available photos of the taxa as far as I know. Feast your eyes upon...

[Thanks to Leo Sham for his amazingly fast and detailed work translating the paper for me. It and some further research- to be expanded upon in upcoming posts- shows some of what I wrote below was incorrect. Hopefully Wikipedia is quick to re-update *innocent whistling*]

"Lancangjiangosaurus cachuensis"

Supposed toothteeth of "Lancangjiangosaurus cachuensis", magnified x1/10, so the photographed area is actually 50x90 cm across. Seems too big to show a tooth, so something may be wrong. After Zhao (1985).

I think this beats Bruhathkayosaurus and Malkani's taxa/rocks as the worst illustration for a new taxon. And yes, that's a high quality scan from the original paper, not a bad photocopy. According to my translation of the caption, it's a tooth in situ. [Actually, it's multiple teeth] Fang et al. (2006) lists it as "Lanchangjiangosaurus cachuensis", which may end up being its name since Zhao is a coauthor. Zhao (1985) states it is very close to Cetiosaurus. It's from the Middle Jurassic Dapuka Group in XinjiangTibet, China. This is also where "Microdontosaurus dayensis" comes from, which is said by Zhao to be a primitive member of Kuhn's discredited group Homalosauropodoidea (peg-toothed taxa, so diplodocids and titanosaurids).

"Damalasaurus laticostalis"

"Damalasaurus laticostalis" dorsal rib in field, magnified x1/13, so the area is about 135x117 cm. After Zhao (1985).

Well that's an improvement. The caption confirms it's a dorsal rib, though it seems like a comparatively useless element to photograph. Note the text lists it as "Damalasaurus magnus", Zhang and Li (1997) list both "D. magnus" and "D. magnas", and Fang et al. (2006) lists "D. laticostalis". Since Zhao is a coauthor of the latter paper, I'm betting "laticostalis" is the "correct" species name. It's noted to be a primitive sauropod, as also stated by Zhao in his earlier (1983) paper. "Damalasaurus" comes from the Early Jurassic Middle Daye Group of Xizang, China.

"Dachungosaurus yunnanensis"

"Dachungosaurus yunnanensis" partial skeleton in field, magnified x1/25, so the area is 2.3x1.5 m. That would make the femur ~955 mm and each dorsal vertebra ~118 mm. After Zhao (1985).

Finally, a good recognizable skeleton. At least nine dorsal vertebrae with associated ribs, and a femur. It's spelled "Dachongosaurus yunnanensis" in the text, but "Dachungosaurus yunnanensis" in the plate caption. This taxon actually seems to be more obscure than even other Zhao nomina nuda like those shown above, since it's not listed or even alluded to in Zhao (1983), Zhang and Li (1997), Weishampel et al. (2004) or Fang et al. (2006). It's generally assumed to be Jurassic because the article is about Jurassic faunas, and from Yunnan based on the species name. Lambert (1990) listed it as a cetiosaurid. The only other technical reference said to mention it is Li (1998), who Ford (Paleofile) said had it in a faunal list. Ford doesn't list a Li, 1998 reference though he does list a Li et al., 1998 reference which is a book I do not have.

So, to shed some light on "Dachongosaurus", I've OCRd the sentences about it (via the tedious but generally functional COCR2 program) and found out it was discovered by He Zhou in the (Sinemurian, Early Jurassic) Dark Red Beds of the Lower Lufeng Series of Yunnan, and is said to be a primitive sauropod with some advanced features. Right there is more valid information on the taxon than has ever appeared in English before. :)

The most well photographed of the bunch is also unfortunately the one already known from photographs of the mounted skeleton online and an illustrated dentary in Dong's (1992) book. The text lists it as "Kunmingosaurus wudingi" and it's from the Early Jurassic Fengjiahe Formation [well, the separation of the Fengjiahe from the Lower Lufeng seems based solely on geography, and I'm not sure yet where Wuding is compared to Chinkshakiangosaurus' Yongren locality; in any case Zhao and most other workers call Kunmingosaurus' stratum Lower Lufeng] of Yunnan along with the possibly synonymous Chinshakiangosaurus (whose femur as photographed by Zhao is shown below; only the dentary has been illustrated otherwise since the rest is in storage [Dong (1992) also illustrated a cervical]).

Also, I can use this time to clear up the situation of "Oshanosaurus youngi", which is usually said to either be a sauropod or ornithischian. Now I see this confusion arose because it is discussed in the same sentence as Dianchungosaurus "elegans" (note it is not the supposed heterodontosaurid D. lufengensis, the holotype of which turned out to be a mesoeucrocodylian). Both are said to be sauropods by Zhao, and are also from the Fengjiahe Formation. [Ah, bad translations.... Both are from the Lower Lufeng Formation, and Dianchungosaurus "elegans" is stated to be a heterodontosaurid while "Oshanosaurus" is a primitive sauropod]

Zhang and Li, 1997. Mesozoic Dinosaur Localities in China and Their Stratigraphy. In Wolberg, Sump and Rosenberg (eds.). Dinofest International, Proceedings of a Symposium sponsered by Arizona State University. A Publication of The Academy of Natural Sciences. 265-273.

Li, Zhang and Cai, 1998. The characteristics of the composition of the trace elements in Jurassic dinosaur bones and Red Beds in Sichuan Basin. Geological Publishing House, Beijing. 155 pp.